In an effort to provide more methods of communication than the standard turn signals and horn (and in some cases the driver's middle finger), Rober set out to build a custom horn rig with multiple sounds. Using a cheap, easily programmable soundboard, an inline inverter, a cheap amp, a cheap PA speaker, some odds and ends, and some good old-fashioned knowhow, he put together a tri-tone system that's both cool and functional.
He mounted the PA speaker under his VW's hood and wired it to a trio of light-up horn buttons he custom installed in his center console. He then programmed the soundboard with two sounds – a friendly two-beat reminder tone and an even friendlier recording of Star Wars' R2-D2 chirping. For some added oomph, he installed a 120 psi airhorn and wired it to a third button for those times when he really needs to grab someone's attention.
Rober posted a great video of his custom horn build on YouTube, and he lays out all the parts with some easy-to-follow instructions. Who knows, maybe this will catch on and in the near future we'll see this as a standard feature on cars and trucks!